how to fix inner tire wear

Oliver Meas1955 · Sunday, 7 November 2021

Quote:

Originally Posted by MrHarris View Post

What's excessive? I checked my fronts, they seem to have even tire wear.

High performance cars are notorious for having uneven rear tire wear. (especially when you have a lowered suspension)

Rear wheel drive performance oriented cars have more negative camber dialed in on the rear suspension to improve handling. (compared to your average family car) If you lower the car from the factory ride height, you unwittingly increase the negative camber of the rear tires. If your suspension/alignment shop gets the setup wrong, you'll end up with too much negative camber. This can accelerate your rear tire wear. (cutting the usable lifespan of the tires in half in severe cases)

Negative camber changes the angle of the tire from it's neutral vertical position. (0 degrees) It causes the angle of the top of the wheel/tire to tilt IN toward the struts/shocks.

As your suspension compresses when you are driving, the tires will "tuck" in even more at the top. (moving towards the struts/shocks)

Positive camber for example would cause the top of the wheel/tire to tilt OUT toward the edges of the outer fender lip. (moving away from the struts/shocks)

The actual adjustments necessary to make dramatic changes to your tire wear, are much smaller than many people think. Your suspension setup is directly related to the tire wear you are experiencing now.

For example:

A change from -1.0 degrees to -1.5 degrees of negative camber, is NOT that significant in regards to tire wear.

But, a change from -1.5 degrees to -2.0 degrees IS significant in regards to tire wear.

And if your TOE setting is off by 1/8", your tire wear will increase. It doesn't sound like such a small adjustment would have such a dramatic effect...but it does.

For minimum tire wear (and power hp/trq loss), the wheels on a given axle should point directly ahead when the car is running in a straight line. (parallel to the chassis) Excessive toe-in (tires pointed IN), or toe-out (tires pointed OUT) will cause the tires to scrub. Since the wheels are always slightly turned relative to the direction of travel, this scrubbing will wear the rubber tread out faster than it normally would. (with the ideal suspension settings)

Too much toe-in will cause accelerated wear at the outboard edges of the tires, while too much toe-out causes wear at the inboard edges.

Suspension settings are crucial for achieving good tire wear.

Unfortunately, many cars do not have the proper alignment settings on their cars to achieve this goal.